Radiological imaging apparatus and method

Abstract

A radiological imaging apparatus and method corrects fixed pattern noise (FPN) generated within the apparatus and suppresses increases in random noise attendant upon FPN correction to provide radiological imaging having improved reliability and image quality. The apparatus has a signal processing circuit that digitizes analog output from a read-out circuit, four FPN memories for storing four dark outputs, a light memory for storing a light output after X-ray exposure of a subject, a CPU for controlling the signal processing circuit as well as FPN and light memories, and a shift resister 7 controlled by the CPU. The method involves averaging multiple dark outputs and subtracting the FPN data average so obtained from the light output which includes the X-ray imaged to enhance picture quality. Since the FPN correction uses FPN data that has been averaged over multiple dark outputs, the method also suppresses random noise generated by the FPN correction for enhanced imaging accuracy.

1. A computer program for controlling a radiological imaging system including a computer executing said program, a radiation source, and a radiation detection unit having a plurality of photoelectric converters arrayed in a matrix-like formation for detecting and converting radiation originated from the radiation source into electrical signals, the program comprising code for performing the following steps:
 a first reading step of reading the electrical signals output by the radiation detection unit, in which the radiation detection unit is operated with applying the radiation originated from the radiation source; 
 a second reading step of reading the electrical signals output by the radiation detection unit, in which the radiation detection unit is operated without applying the radiation, wherein said second reading step is performed at least twice; 
 an averaging step of avenging the results of said second reading step so as to obtain an average signal value thereof; and 
 a subtraction step of subtracting the average signal value from a signal value obtained at said first reading step. 
 
     
     
       2. The program of  claim 1 , wherein said second reading step is performed at least twice before said first reading step. 
     
     
       3. A computer readable medium containing the computer program of  claim 2 . 
     
     
       4. The program of  claim 1 , wherein said second reading step is performed at least twice after said first reading step. 
     
     
       5. A computer readable medium containing the computer program of  claim 4 . 
     
     
       6. A computer readable medium containing the computer program of  claim 1 .